Techtrend

Short Circuit on Memory Lane

By Jerry Flint
WardsAuto.com, Oct 22, 2009 1:20 PM

Let’s take a drive down memory lane and remember some of the “cars of tomorrow.”

In 1963, there was the Chrysler turbine car, a real beauty. It was powerful, efficient and could run on just about any fuel, including diesel and vegetable oil.

After a decade of development, Chrysler built about 50 for consumer trials and then threw in the towel.

Along with many advantages, the turbine car had lots of unforeseen problems, including troublesome emissions and exhaust that could melt the car behind you at stoplights. It also sounded like a giant vacuum cleaner.

Next up is the Wankel rotary engine. Compact and powerful, it was the toast of the automotive world for a few years in the 1970s. GM spent a bundle trying to bring one to market but gave up because of emissions issues. Intellectuals and environmentalists berated Detroit for letting little Mazda take the lead in introducing the technology.

Years later, Mazda is the only auto maker that still cares about the rotary-engine concept.

In the 1990s, GM invested heavily in the EV1 electric car. It attracted a few hundred fanatical fans and no one else.

BMW has been touting cars with internal-combustion engines that burn hydrogen, instead of gasoline, for decades. We have not heard much about these cars of the future lately. Instead, BMW is hyping hybrid-electric vehicles and pure electrics.

Our next stop on memory lane is the fuel cell. After spending billions on research, numerous auto makers still deliver lip service to fuel cells. Honda and a few others have some fuel-cell-powered electric cars running around. But the U.S. government has lost interest in them and isn’t offering to fund much research anymore.

Then there’s compressed natural gas. CNG has been used to fuel vehicles in the U.S. and overseas for decades. Despite an elaborate public-relations blitz by billionaire T. Boone Pickens, that alternative fuel isn’t likely to expand much, either. Like hydrogen and ethanol, there is no refueling infrastructure.

That brings us to today’s current fascination with battery-powered EVs. They were the stars of the Frankfurt and Tokyo auto shows and almost every major auto maker is showing off some kind of EV.

There will be some battery-powered cars, but far fewer than true believers predict. Range, cost and recharging issues will not be solved anytime soon.

Some fantasize about leasing batteries to hold down the cost. But that strategy doesn’t hold down cost; it just spreads it out.

Recharging is the biggest unsolved issue. It can take eight to 12 hours to recharge with ordinary household current. There’s talk of fast recharging, two hours or less, but that presents cost, battery life and perhaps safety issues, as well.

Certainly some consumers will want EVs, just as some now crave the Daimler Smart car. But the number of vehicle buyers who will shell out hard-earned dollars just to save the planet are small.

Saving the Earth is fine, but green consumers won’t support the production of hundreds of thousands, or millions, of EVs. Not yet and maybe never.

Jerry Flint is a columnist for, and former senior editor of, Forbes Magazine.

Nissan bringing new CVT, small engine family to market
07-10월-2009 20:00 GMT

Nissan and Jatco jointly developed the CVT that employs a sub-planetary gear two-speed geartrain that provides a ratio spread of 7.3.

“The concept has been with us—and maybe with others—for a very long time,” confided Hitoshi Suzuki, Senior Development Engineer at Jatco, the specialist supplier of automatic and continuously variable transmissions (CVTs).

The concept refers to a sub-geartrain added to a CVT, thereby widening the transmission’s ratio spread. In this case, for Nissan, the Xtronic transmission is the steel push-belt-and-pulley type. The ratio spread ranges between a smallish 4.5 up to a fraction over 6.0, according to Suzuki. Recently Subaru (which makes its own CVTs) has achieved an impressive 6.3 using a pull-chain-and-pulley arrangement.

Link: http://www.sae.org/mags/aei/7030/
The Jatco CVT employs a sub-geartrain, a planetary gear unit, that provides two ranges: low and high. The ratio spread is a 7.3.

Jointly developed by Nissan and Jatco, the unit allows for a compact size and light weight. The two pulleys are positioned side by side vs. the conventional CVT’s stacked-at-an-angle placement. The pulleys are completely out of the fluid sump, eliminating the slushing of fluid altogether.

Frictional losses have been reduced by 30%, Nissan claims, and fuel economy improvement by 10% vs. a comparable, conventional CVT-equipped car.

A Versa hatchback equipped with this transmission was available for test-driving by AEI. The car moves off in the sub-geartrain’s Low with the CVT obviously in the lowest ratio, producing brisk acceleration.

The torque converter locks up fully at 14 to 15 km/h (8.7 to 9.3 mph). At about 20 km/h (12 mph), the sub-gearbox shifts into high and keeps it thereafter. On deceleration and braking, the CVT stays in high to a full stop, fuel economy being primary objective here.

The next-generation Xtronic CVT is best suited to small-displacement engines and will likely be complemented by the company’s dual-injector technology.

Nissan will deploy its next-generation small-displacement gasoline engine family in its small and compact cars, beginning in 2010. The new inline four-cylinder series will likely have a median displacement of 1.5 L and will be equipped with continuously variable valve timing control (CVTC) on both the intake and exhaust camshafts.

The unique feature is that each cylinder is fed by two port injectors. The new injector nozzle has 18 miniscule holes vs. a more common single injector with 12 holes. The injectors are placed in the intake ports closer to the intake valve openings. They inject fuel in wide-angle spray cones, with droplet size reduced from the single 12-hole type’s 70 µm (2800 µin) to 30 µm (1200 µin). This promotes faster and finer atomization of the incoming charge, according to Nissan engineers.

The dual-injector system, developed by Denso, is relatively straightforward. It is simpler and lighter in weight than a comparable direct-injection system, according to Nissan. Injection pressure is port-injection-norm, much lower than that of a typical direct-injection (DI), therefore its hardware is less expensive.

Nissan quotes a cost reduction of 60% vs. DI. Stable combustion allows a generous internal exhaust gas recirculation introduced during a larger overlap by the dual CVTC, which improves fuel economy and reduces pumping loss.

The dual-injector system achieves a 4% improvement in fuel efficiency vs. a conventional single-injector port-injection engine, according to Nissan.

The other significant benefit of the system is that the amount of rare metals in the catalytic converter may be greatly reduced by nearly 50%, as the catalyst would have to cleanse less hydrocarbon emissions.
Jack Yamaguchi

Lotus Engineering unveils ICE for range-extender hybrids
14-9월-2009 22:12 GMT

Lotus’ range extender for series hybrids produces 35 kW.

At the Frankfurt Motor Show, Lotus Engineering unveiled a small range-extender engine for series-type hybrid applications.

Incorporating some advanced design and manufacturing techniques, the three-cylinder, 1.2-L unit produces 35 kW (47 hp) at 3500 rpm via an integrated electrical generator. Weight has been kept low at 56 kg (123 lb).

Lotus Engineering Technical Director, Simon Wood, said: “Designing the Lotus Range Extender purely for use in series hybrids has allowed us to develop an optimized engine that has high thermal efficiency, low fuel consumption, multi-fuel capability and low-cost architecture.”

He added that the engine is designed specifically to fit the operating range demanded by a series-type hybrid, whereas most series hybrid vehicles currently being developed would use adaptations of existing, conventional engines. The operating efficiency of such ICEs is usually compromised because they have been designed for a wide range of operating conditions.

In a series hybrid the combustion engine is connected to an electricity generator to provide an efficient energy source to power the vehicle’s electric motor or charge its battery – which can also power the electric motor.

With strict weight targets to achieve, Lotus opted for an aluminum monoblock architecture, integrating the cylinder block, cylinder head and exhaust manifolds in a single casting. Advantages include less engine mass, and lower assembly costs with reduced parts count. The range extender has been designed to give improved packaging, emissions and durability.

The engine is optimized between two power generation points:1500 rpm, when it produces 15 kW (20 hp), and 3500 rpm which gives 35 kW (47 hp) via the integrated electrical generator.

A combustion system featuring two valves per cylinder and port fuel injection is used. The engine is designed and calibrated to handle gasoline or alcohol-based fuels.

The need to overcome the potentially high cost of series hybrid technology is essential for market success. Lotus believes that the efficiency of its new range extender also will offer benefits in terms of downsized (and less expensive) batteries. Lotus Engineering designed the engine using production methodologies with parts procured from low-volume potential suppliers.

The decision to use monoblock construction not only avoids the need for a cylinder head gasket but eliminates some seventeen components. The water jacket is also said to be better optimised.

Tse of an integrated exhaust manifold also reduces parts count by about eighteen, with associated inventory, production logistics and aftermarket costs. Obviating the need for a separate exhaust manifold also saves weight.

Further plusses are a reduction in emissions via a faster light-off of the engine’s close-coupled catalytic converter, with a reduction in heat loss between exhaust port and catalyst inlet, claims Lotus Engineering. The development engineers also focused on reduced NVH.

The Lotus range extender forms part of the U.K.’s “Limo Green” project funded by the Technology Strategy Board, a collaboration which also involves Jaguar, MIRA, and Caparo Technologies aimed at demonstrating a large, lightweight, premium sedan, producing CO2 emissions of less than 120 g/km.
Stuart Birch

Bosch unveils new technology packages to boost gasoline and diesel fuel efficiency
06-10월-2009 18:51 GMT

By 2015, technology improvements could increase fuel efficiency of diesel and gasoline engines by 30%, thus reducing CO2 emissions by the same amount, says Bosch’s Leonhard.

Bosch has bundled enabling powertrain technologies for gasoline and diesel engines into various packages, to further increase the internal-combustion engine’s fuel economy. At the recent Frankfurt Motor Show, Dr. Rolf Leonhard, Executive Vice President of Development for diesel systems, explained his company’s roadmap.

“Compared to a four-cylinder port-injection gasoline engine with 100 kW power and 200 N·m torque, installed in a reference car with a curb weight of 1.4 t, our first gasoline technology package can offer up to 22% better fuel economy at Euro 6 emissions level,” Leonhard said.

To achieve this improvement, direct injection and turbocharging at 1.8 bar (26 psi) level are used to enable downsizing the engine displacement from 2.0 L to 1.4 L without compromising power or torque.

“Turbocharging is absolutely essential to make sure that downsizing does not mean downgrading,” Leonhard noted. This technology “package” also includes the control function for variable valve timing on the intake and exhaust sides to improve low-rpm torque via cylinder scavenging. The package is completed by improved thermal management and a start-stop system.

The second technology package developed by the supplier is based on a more aggressive downsizing approach. This reduces the number of cylinders to three, brings down displacement to 1.1 L, increases the charge pressure to 2.4 bar (35 psi) and adds valve lift control. As a result, fuel economy can improve by up to 30% on a port-injection engine.

“If both packages are combined, the vehicle manufacturer harvests up to 30% better fuel economy, which brings down the CO2 emissions from 182 g/km to 130 g/km for 1000 euros added cost (per vehicle) in 2015,” Leonhard explained. “If you consider the expected European CO2 penalty of around 95 euros per gram of CO2, this is an absolute bargain.”

Adding Bosch’s hybrid technology package, a 25-kW electric engine and 1-kWh battery, could give the 1.1-L gasoline engine hybrid nearly 40% better fuel economy than that of port injection technology.

Working the trade-off between NOx and consumption

The company’s diesel technology packages are very similar, with the exception that direct injection is standard in modern diesel engines. Typical diesels offer 30% better fuel economy than today’s standard port-injection gasoline engines anyway.

The first diesel package includes downsizing of a four-cylinder 2.0-L engine to 1.6 L capacity. Improving combustion plays a key role in this package, which is tailored to increase fuel efficiency by up to 22% compared to basic contemporary diesel technology.

Diesel package number two offers a remarkable strategy to improve fuel consumption by up to 28%: “Normally we will not need DeNOx technology to meet Euro 6 legislation in smaller diesel passenger cars,” Leonhard said. “However, DeNOx technology such as SCR or a NOx storage catalyst can help to increase fuel efficiency by another 5-7%.”

For that purpose, Leonhard suggests to accept a higher engine-out NOx level and to add a DeNOx system with 50% conversion rate. “This is efficient to meet Euro 6 NOx levels. At the same time, it makes a further reduction of the diesel engine’s fuel consumption possible.”

More aggressive downsizing of the diesel engine to 1.2 L and just three cylinders is at the core of diesel package number three, which aims at up to 33% better fuel efficiency. By adding a hybrid option of the same size as the one in the third gasoline technology package, the diesel could ultimately achieve up to 40% better fuel efficiency.

To supply lithium-ion batteries as part of a hybrid drive, Bosch founded the SB LiMotive joint venture with Korea’s Samsung SDI in September 2008. Series production of lithium-ion cells is planned to commence in 2011; BMW will be the first customer. The automaker will use the cells for its Megacity electric vehicle.
Joerg Christoffel

Link: http://www.sae.org/mags/aei/7011/

Honda readies innovative new DCT and V4 engine for 2010 bikes
13-10월-2009 14:36 GMT

The 2010 VFR1200F offers the first dual-clutch transmission by a motorcycle OEM. The Honda-developed system features two shift modes and paddle-type controls.

Honda is the world’s greatest proponent of the V4 engine configuration. Since 1982, the company has mass-produced various sport, cruiser, and sport-touring motorcycles powered by dohc 16-valve, liquid-cooled V4s in cylinder displacements ranging from 400 cc to 1.3 L.

Honda’s bike engineers like the V4 for its compact packaging, smooth power delivery, unique exhaust sound, and race-winning durability. Honda also has used the 800-cc VFR V4 to transfer its VTEC variable valvetrain technology from its automobile group to the motorcycle side.

Clearly Honda intends to keep the V4 as a core engine family showcasing the latest technologies for greater fuel efficiency, reduced emissions, and higher output. The next VFR will debut as a 2010 model, and it is so important to Honda that the company spent much of this year strategically using the Internet to release information about the innovative new V4 engine and an optional dual-clutch transmission (DCT).

Honda will deploy the DCT first in the VFR and later in other touring-model motorcycle ranges.

In late summer, patent drawings of the new 1.2-L (actually 1,237-cc) V4’s crankshaft and crankcase assembly surfaced on various enthusiast websites. These were followed by factory cutaway photographs of the VFR’s DCT—the first use of dual-clutch transmission technology in a production motorcycle.

And recently, Tsutomo Iishi, the VFR1200F’s program’s lead engineer, appeared on YouTube in a company-produced video interview, where he explains key highlights of the V4. Such “viral” marketing techniques and “unofficial-yet-official” leaks by Honda are in the vanguard of how OEMs are introducing new products and technologies to a global audience. Engineers, take note.

Iishi-san spent much of this decade on Honda’s MotoGP development team working on the RC211V, the company’s 990-cc V5 race engine, followed by the 800-cc RC212V, a V4. His experience with these engine types helped influence key design bogeys of the production VFR1200, he explained in the video interview.

“We didn’t go for top-end speed and peak top-end performance in the design of this engine,” he said. Instead, a linear power delivery, greater overall efficiency, and the engine’s exhaust tone were major design bogeys.

The V4’s compact, forged steel crankshaft offsets its connecting rod journals by 28°. The front cylinders (No. 1 and 4) are spaced wider apart than the rear cylinders No. 2 and 3. This configuration helps make the rear half of the engine much narrower than the front, thus slimming the center of the motorcycle and providing more legroom for the rider in this critical area.

The Honda video illustrates how the new VFR’s front cylinder bank, though wider than the rear, is still narrower than the single bank of Honda’s current CBR1000 inline-four—quite a packaging feat.

The crankshaft gives a 1-2-4-3 firing order. Honda calls this a “Symmetrically Coupled Phase-Shift Crankshaft” and combined with a 76° splay between the cylinder banks, the arrangement gives perfect primary balance. Its smooth running characteristics negate the need for a counter-rotating balance shaft.

Another clever engineering touch with packaging and operational benefits is the use of Honda’s Unicam sohc valvetrain on the front and rear cylinder heads. According to Iishi, this allowed engineers to reduce the size of the engine’s exhaust side, allowing the powerplant to fit a very compact chassis.

The Unicam was adopted from Honda’s proven CRF450 single-cylinder motocross engine. It uses a single camshaft to operate each head’s intake valves via direct-acting bucket type tappets, and long rocker arms to operate the exhaust valves.

Honda engineers claim the Unicam head is lighter than a dohc type. The arrangement also allows an ultraflat combustion chamber, which allows engineers to optimize the combustion process. Ignition timing is 104°-256°-104°-256°, a setup that helps create the V4’s unique exhaust note.

It was long rumored that the new VFR’s rear cylinder head would be a dohc type with four bucket-type tappets and fitted with a new iteration of the current VFR800’s Hyper-VTEC system. Honda had developed a cylinder-deactivation system allowing the engine to operate in two- or four-valve mode, depending on load, as well as being able to completely deactivate two cylinders.

This sophisticated, complex system would allow the 1.2-L V4 to effectively function as a 600-cc twin, providing up to 30% greater steady-state cruising efficiency. However, it was not implemented in the 2010 VFR.

Honda claims 90% of the V4’s peak torque is available at 4000 rpm. The engine’s redline is 10,200 rpm. The company has not yet released output figures.

Regarding the optional DCT, it is the latest in Honda’s wide-ranging R&D for new methods of transferring power in two-wheelers. As it does in cars, the dual-clutch gearbox provides precise, rapid, semi-automatic gear changing.

To provide maximum flexibility to the rider, the new DCT features three operating modes—two full-auto modes (D-mode for regular operation and S-mode for sporty riding), and a six-speed manual mode, which delivers the same shift feel as a manual transmission.

The new transmission was developed exclusively by Honda, which has scaled the transmission architecture for use with large-displacement V4 engines in the VFR and ST model ranges.

Bikes equipped with the standard 6-speed manual gearbox feature a slipper-type clutch, as typically fitted to road racing bikes. The slipper mechanism helps minimize the effect of deceleration torque on the drive wheel when the rider uses engine braking to slow the machine.

All VFRs feature shaft final drive for the first time, replacing chain drive. The new arrangement uses a constant-velocity universal joint to compensate for changes in driveline length due to rear suspension travel.

Watch for more details of the new Honda VFR1200F, its V4 engine, and DCT in upcoming issues of this publication.
Lindsay Brooke

Link: http://www.sae.org/mags/aei/7070/